Scintillator plates of crystalline luminophores are utilized in radiation detectors such as, for example, in Anger cameras or in PET systems. The manufacture of such scintillator plates requires numerous steps. After the crystallization of the scintillator bodies, the plates must be cut into the required shape and ground on all sides. Subsequently, the scintillator bodies are optically coupled to a glass plate, behind which the luminescent light can then be measured with suitable photodetectors.
Since some of the luminophores are very moisture-sensitive and fracture-prone substances such as Nal or Csl, the other surfaces of the scintillator plates are protected against mechanical influences and against moisture. A cap, preferably of aluminum, serves this purpose. This cap can be provided with a layer at its inside surface for better reflection of the luminescent light. Laterally, the air gap between scintillator and cap is sealed with a rubber ring or the like to prevent the penetration of moisture. All of the above-referenced method steps must be implemented in special rooms with a moisture-free atmosphere in order to prevent harmful effects of moisture on the luminophore.
EP 0700454 discloses a casting process for manufacturing the crystal bodies for the scintillator plates wherein a melt flows into a cooled casting mold and solidifies therein. Stable melt vessels are required for the growth of halogenide crystals since the crucible walls are previously attacked by the melt given the presence of slight traces of water or hydroxide molecules. As a result thereof, the melt adheres firmly on the crucible walls after solidification. During cooling, the enormous tensile stresses occurring due to the thermal contraction of the melt can lead to the destruction of the crucible. Of course, this phenomena makes the process more expensive.
Therefore, there is a need to improve such methods or a similar methods for manufacturing crystal bodies to the effect that single-crystals having especially large diameters can be produced therewith in a more cost-beneficial and simplified way.